A study by the University of Nebraska has come under fire from the Center for Rural Affairs. The study concludes large-scale hog operations do not have a negative effect on small family farms. Center spokesman John Crabtree says the research in the study is flawed. Crabtree says the most recent data used in the study was 1993, and says dramatic changes have happened since then..Crabtree says the worry is that government policy may be made using the assumptions in the report that don’t take into account recent changes.Crabtree says another flaw in the study deals with what constitutes a large hog operation. He says the study used one thousand hogs as a threshold instead of 50-thousand or more which poses a bigger threat. John Allen, the professor at Nebraska who conducted the study, says he stands by his research methods.